The particular emphasis of this book is on new approaches to the notch effect problem in fatigue and fracture, and in particular the volumetric approach. These new methods are introduced in an attempt to replace the hot spot method, which suffers from some degree of empiricism. The work has given rise to a new field: notch fracture mechanics, in which a crack is considered as a particular case of a notch. Theoretical and practical aspects are presented in both fracture and fatigue. Special attention is paid to welded joints. This work is particularly recommended to engineers involved in safety design. Readers should possess adequate skill in strength of materials and fracture mechanics.

As Directors of this NATO Workshop, we welcome this opportunity to record formally our thanks to the NATO Scientific Affairs Division for making our meeting possible through generous financial support and encouragement. This meeting has two purposes: the first obvious one because we have collected scientists from East, far East and west to discuss new development in the field of fracture mechanics: the notch fracture mechanics. The second is less obvious but perhaps in longer term more important that is the building of bridges between scientists in the frame of a network called Without Walls Institute on Notch Effects in Fatigue and Fracture". Physical perception of notch effects is not so easy to understand as the presence of a geometrical discontinuity as a worst effect than the simple reduction of cross section. Notch effects in fatigue and fracture is characterised by the following fundamental fact: it is not the maximum local stress or stress which governs the phenomena of fatigue and fracture. The physic shows that a process volume is needed probably to store the necessary energy for starting and propagating the phenomenon. This is a rupture of the traditional "strength of material" school which always give the prior importance of the local maximum stress. This concept of process volume was strongly affirmed during this workshop.

The particular emphasis of this book is on new approaches to the notch effect problem in fatigue and fracture, and in particular the volumetric approach. These new methods are introduced in an attempt to replace the hot spot method, which suffers from some degree of empiricism. The work has given rise to a new field: notch fracture mechanics, in which a crack is considered as a particular case of a notch. Theoretical and practical aspects are presented in both fracture and fatigue. Special attention is paid to welded joints. This work is particularly recommended to engineers involved in safety design. Readers should possess adequate skill in strength of materials and fracture mechanics.

As Directors of this NATO Workshop, we welcome this opportunity to record formally our thanks to the NATO Scientific Affairs Division for making our meeting possible through generous financial support and encouragement. This meeting has two purposes: the first obvious one because we have collected scientists from East, far East and west to discuss new development in the field of fracture mechanics: the notch fracture mechanics. The second is less obvious but perhaps in longer term more important that is the building of bridges between scientists in the frame of a network called Without Walls Institute on Notch Effects in Fatigue and Fracture". Physical perception of notch effects is not so easy to understand as the presence of a geometrical discontinuity as a worst effect than the simple reduction of cross section. Notch effects in fatigue and fracture is characterised by the following fundamental fact: it is not the maximum local stress or stress which governs the phenomena of fatigue and fracture. The physic shows that a process volume is needed probably to store the necessary energy for starting and propagating the phenomenon. This is a rupture of the traditional "strength of material" school which always give the prior importance of the local maximum stress. This concept of process volume was strongly affirmed during this workshop.